The present invention relates to a search technique to search for and obtain broadcasted information precisely after having been broadcasted.
There have hitherto been data base systems for searching data stored as a data base and accumulated on a computer-system. A user retrieves desired information by operating a terminal device which is connected to a data base system directly, or through a network. For example, the user inputs from the terminal device a keyword representing the desired information; and the data base system carries out a search operation on the basis of the input keyword. The search results are supplied through the terminal device to the user. When the amount of information thus supplied is large, the user inputs additional keywords to perform a narrower search operation on the supplied information.
The case where a user searches music data accumulated in a data base system will be described. For example, on the basis of the search result, the user may retrieve title information, etc. of a CD (Compact Disc) on which desired music pieces are recorded, which is useful if the user wishes to purchase the CD. Here, the music data is information related to the music pieces, and it constitutes various information such as the titles of the music pieces, the names of the artists, the record album title, that is, the title of the music CD, the year of recording or public performance, the selling agency, etc. The music data may contain the audio data of the music data themselves. In the data base system, keywords, such as the artist's name, the title of the music piece, the record album title, and the like are appended to the music data as appendant information.
Let it be assumed that a user likes a music piece which is being broadcasted on a radio station and wishes to obtain information on that music piece. After the broadcast, the user searches the music data base by inputting the keywords that are appended to the music data, which keywords had been included in the announcer's introduction of that music piece. Of course, if the keywords are not properly input, a successful search for that music piece will not be obtained. Accordingly, in the related art, there is the problem that the user will not obtain the information he desires if the user forgets the appendant information of the music piece that was broadcasted.
One might consider the possibility that the user carries a terminal device operable at any time for searching a music data base so that he may use the terminal device to perform a search operation whenever a favorite music piece is broadcasted However, it is very cumbersome to carry the terminal device at all times.
One might also consider the case where the user first begins to listen to the music piece from some midpoint thereof Since he could not hear the announcer's introduction, the user cannot know the appendant information of the music piece, and thus he cannot know what should be input as a keyword.
Now, for digital broadcast, the appendant information may be superposed on the broadcasted music data and may not be part of the announcer's introduction. The user can obtain the appendant information from the broadcasted digital data. However, this requires that appendant information be created and superposed on every music data to be transmitted from a broadcast station, and thus a large load is imposed on the broadcast station. This also requires the user's reception device be designed to pick up the appendant information thus superposed.